1. Field of the Invention
The present invention relates to a liquid crystal display driving device and a method of driving a liquid crystal display. More particularly, the present invention relates to a driving method and device using a halftone gray driving method in enlarging an image, wherein the driving device and method are capable of enhancing viewing angle characteristics of a liquid crystal display.
2. Description of the Related Art
Generally, liquid crystal display (LCD) devices include a liquid crystal display panel having a plurality of liquid crystal cells arranged in a matrix pattern and a driver integrated circuit (IC) for driving the liquid crystal cells. Data signals containing image information are received by the driver IC and are applied to individual liquid crystal cells. Accordingly, light transmittance characteristics of the individual liquid crystal cells may be controlled by the applied data signals to display images across the LCD panel.
The liquid crystal panel generally includes a color filter substrate separated from a thin film transistor array substrate by a layer of liquid crystal material. A common electrode and pixel electrodes are formed on the opposing surfaces of the color filter and thin film transistor array substrates, respectively, and apply electric fields to the layer of liquid crystal material. The pixel electrodes are formed within liquid crystal cells on the thin film transistor array substrate and the common electrode is formed over the entire surface of the color filter substrate. By controlling voltages applied to the pixel electrodes while a voltage is applied to the common electrode, light transmittance characteristics of the individual liquid crystal cells is controlled.
The thin film transistor array substrate supports a plurality of data lines and a plurality of gate lines crossing the data lines. Liquid crystal cells are defined where the gate and data lines cross each other. The data lines transmit data signals supplied from a data driver IC to the liquid crystal cells while the gate lines transmit scan signals supplied from a gate driver IC to the liquid crystal cells.
The gate driver IC sequentially supplies a scan signal to the plurality of gate lines such that the liquid crystal cells are sequentially selected one line at a time. Data signals are supplied from the data driver IC to the liquid crystal cells within the selected line.
Switching devices such as thin film transistors are provided to control the voltage applied to the pixel electrode by liquid crystal cells. Via the gate lines, scan signals are applied to gate electrodes of the thin film transistors to form a conductive channel between a source/drain electrode of the thin film transistor within the liquid crystal cell. Via the data lines, data signals are applied to source electrodes of the thin film transistors and then to pixel electrodes to control the light transmittance characteristics of individual liquid crystal cells.
The LCD panel described above will now be explained in detail with reference to the accompanying drawings.
FIG. 1 illustrates a schematic view of a related art LCD panel including the thin film transistor array and color filter substrates attached to, and facing each other.
Referring to FIG. 1, the LCD panel 10 includes an image display area 13 having a plurality of liquid crystal cells arranged in a matrix pattern, a gate pad area 14 connected to a plurality of gate lines within the image display area 13, and a data pad area 15 connected to a plurality of data lines within the image display area 13.
The gate and data pad areas 14 and 15, respectively, are formed at peripheral portions of the thin film transistor array substrate 11 that do not overlap with the color filter substrate 12. The gate pad area 14 receives scan signals from the gate driver IC and supplies the received scan signals to the plurality of gate lines within the image display area 13. The data pad area 15 receives image information from the data driver IC and supplies the received image information to the plurality of data lines within the image display area 13.
Though not shown in FIG. 1, switching devices such as thin film transistors are formed where the plurality of gate and data lines cross each other on the thin film transistor array substrate 11 and within the image display area 13. The thin film transistors control the light transmittance characteristics of the liquid crystal cells within which they are formed. Pixel electrodes are connected to corresponding thin film transistors and drive the liquid crystal cells. A passivation film is formed over the entire surface of the thin film transistor and protects the thin film transistor.
A plurality of color filters, a black matrix, a common transparent electrode, and counter electrodes of the pixel electrodes are formed on the color filter substrate 12 and within the image display area 13. The color filters are coated within individual cell regions and separated by the black matrix.
Spacers are provided between the thin film transistor array and color filter substrates 11 and 12 to create a uniform cell gap that may be filled with liquid crystal material. The thin film transistor array and color filter substrates 11 and 12 are attached by a sealant 16 formed at a periphery of the image display area 13.
The LCD device illustrated in FIG. 1, however, has a small optical viewing angle and displays images at lower brightness levels than other display devices. Accordingly, recent LCD development seeks to increase the optical viewing angle and light transmittance characteristics.